If you've ever lost a significant amount of weight by committing to a healthier lifestyle, you're familiar with just how difficult it can be to keep it off, despite your most dedicated efforts. Even when you maintain healthful practices, it's normal to witness a fluctuation in weight—gaining, losing, and regaining over time. "For a long time, it was assumed that this was because dieters lapse back into eating habits that caused them to gain weight in the first place," notes Monica Reinagel, MS, LD/N, CNS, in a podcast on Scientific American.

Over the past several years, a series of studies from the Weizmann Institute of Science in Israel shows that something else is at work—and reveals a strategy that could stop the cycle.

It all comes down to gut health. "When we gain weight, the makeup of our intestinal bacteria also changes in ways that tend to promote further weight gain," explains Reinagal. "When we lose weight, however, our intestinal bacteria don't change back to the bacteria profile we had before we gained that weight." The researchers found that by transferring the bacteria of healthy mice into the stomachs of overweight mice, they could end the yo-yo dieting effects. While transferring bacteria isn't really a feasible solution for humans facing the same problem, the study also found that by bringing flavanoids into the picture, fat oxidation acceleration and metabolism were boosted—essentially overriding the effects of these weight-gaining bacteria.

The particular metabolism-boosting flavanoids Reinagal calls out are naringenin—especially plentiful in grapefruit and grapefruit juice—and apigenin—particularly abundant in chamomile tea and parsley. So if you're looking to reliably transform the bacteria profile in your stomach from one that favors weight gain to one with a healthy, productive metabolism, try incorporating these nutrient-rich foods into your diet to reset your gut.